Every time I need to install Python on OSX or whenever a colleague asks for help, I have to search fo the most updated instructions on Google, and every time I find different ways of doing the exact same thing.

Tired of this, I decided to write down my own notes. Please note that I don't claim this to be the best way of installing Python on OSX. It works fine for me so use it at your own risk.

Requirements

To follow these instructions you need to at least have installed brew on OSX. Please follow the instructions on the official website: https://brew.sh

Installing Python 3.7.x and Python 2.7.x

Even if I strongly suggest to start every new project with Python 3 (since Python 2 will only be supported until the end of 2019), there may be use cases when version 2 is still required, so I will give you the instructions to install both.

Add the Python locations to PATH

You will need to close your terminal and reopen it for the changes to be applied. Once you have done it, you can verify if Python 3 and Python 2 have been installed correctly:

python --version
Python 3.7.1

and

python2 --version
Python 2.7.15

Install virtualenv and virtualenvwrapper

When working with Python, it's a good thing not to install packages system wide, but confine them in virtual environments. A good and well tested way of doing that is to use virtualenv (and its companion virtualenvwrapper) which makes the most common operations easier.

pip install virtualenv
pip install virtualenvwrapper

Those (and only those) two packages will be installed system wide, because we will need them to be available outside of a virtual environment.

If you see something similar, it means that the virtual environment has been created correctly. Please note that by default this command will create an environment base on Python 3. Do you need to create one for Python 2? No problem, you just need to do the following: